From my understanding the elemental resists give you a small chance to resist an attack entirely, so you would have something like Thunderstorm and take no damage. It would be nice for them to make these useful.

I always wanted to try it out too, get a set of ilv crafted gear. Pimp it out with elemental resistance gear and see what happens. It would be nice to give a elemental reduction in general rather than a chance at resisting entirely.